<?php
/**
 * CGettextMessageSource class file.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @link http://www.yiiframework.com/
 * @copyright Copyright &copy; 2008-2011 Yii Software LLC
 * @license http://www.yiiframework.com/license/
 */

/**
 * CGettextMessageSource represents a message source that is based on GNU Gettext.
 *
 * Each CGettextMessageSource instance represents the message tranlations
 * for a single domain. And each message category represents a message context
 * in Gettext. Translated messages are stored as either a MO or PO file,
 * depending on the {@link useMoFile} property value.
 *
 * All translations are saved under the {@link basePath} directory.
 * Translations in one language are kept as MO or PO files under an individual
 * subdirectory whose name is the language ID. The file name is specified via
 * {@link catalog} property, which defaults to 'messages'.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @version $Id: CGettextMessageSource.php 2798 2011-01-01 19:29:03Z qiang.xue $
 * @package system.i18n
 * @since 1.0
 */
class CGettextMessageSource extends CMessageSource
{
    const CACHE_KEY_PREFIX='Yii.CGettextMessageSource.';
    const MO_FILE_EXT='.mo';
    const PO_FILE_EXT='.po';

    /**
     * @var integer the time in seconds that the messages can remain valid in cache.
     * Defaults to 0, meaning the caching is disabled.
     */
    public $cachingDuration=0;
    /**
     * @var string the ID of the cache application component that is used to cache the messages.
     * Defaults to 'cache' which refers to the primary cache application component.
     * Set this property to false if you want to disable caching the messages.
     * @since 1.0.10
     */
    public $cacheID='cache';
    /**
     * @var string the base path for all translated messages. Defaults to null, meaning
     * the "messages" subdirectory of the application directory (e.g. "protected/messages").
     */
    public $basePath;
    /**
     * @var boolean whether to load messages from MO files. Defaults to true.
     * If false, messages will be loaded from PO files.
     */
    public $useMoFile=true;
    /**
     * @var boolean whether to use Big Endian to read and write MO files.
     * Defaults to false. This property is only used when {@link useMoFile} is true.
     */
    public $useBigEndian=false;
    /**
     * @var string the message catalog name. This is the name of the message file (without extension)
     * that stores the translated messages. Defaults to 'messages'.
     */
    public $catalog='messages';

    /**
     * Initializes the application component.
     * This method overrides the parent implementation by preprocessing
     * the user request data.
     */
    public function init()
    {
        parent::init();
        if($this->basePath===null)
        $this->basePath=Yii::getPathOfAlias('application.messages');
    }

    /**
     * Loads the message translation for the specified language and category.
     * @param string $category the message category
     * @param string $language the target language
     * @return array the loaded messages
     */
    protected function loadMessages($category, $language)
    {
        $messageFile=$this->basePath . DIRECTORY_SEPARATOR . $language . DIRECTORY_SEPARATOR . $this->catalog;
        if($this->useMoFile)
        $messageFile.=self::MO_FILE_EXT;
        else
        $messageFile.=self::PO_FILE_EXT;

        if ($this->cachingDuration > 0 && $this->cacheID!==false && ($cache=Yii::app()->getComponent($this->cacheID))!==null)
        {
            $key = self::CACHE_KEY_PREFIX . $messageFile;
            if (($data=$cache->get($key)) !== false)
            return unserialize($data);
        }

        if (is_file($messageFile))
        {
            if($this->useMoFile)
            $file=new CGettextMoFile($this->useBigEndian);
            else
            $file=new CGettextPoFile();
            $messages=$file->load($messageFile,$category);
            if(isset($cache))
            {
                $dependency=new CFileCacheDependency($messageFile);
                $cache->set($key,serialize($messages),$this->cachingDuration,$dependency);
            }
            return $messages;
        }
        else
        return array();
    }
}
